Many compounds are known which exhibit some degree of antiinflammatory activity.
For example, British Pat. No. 1,099,389 discloses certain 2,4-disubstituted thiazoles which are known to be antiinflammatory. However, these compounds suffer from certain inherent deficiencies which limit their utility as antiinflammatory drugs. Also, in U.S. Pat. No. 3,796,800 is disclosed another group of thiazoles which exhibit antiinflammatory properties. These compounds are generally identified by the formula: ##STR2## wherein R is lower alkyl (e.g., --CH.sub.3), or N-aminocarbamoyl; R" and R"' are independently selected from the group consisting of hydrogen, lower alkyl (e.g., --C.sub.2 H.sub.5) and lower acyl (e.g., --COCH.sub.3); and R' is hydrogen, CONHR.sub.1 or CONR.sub.2 R.sub.3, wherein R.sub.1 is phenyl, mono-, di- or tri-(lower)alkylphenyl, cyclohexyl, or amino; R.sub.2 is lower alkyl (C.sub.1 -C.sub.3); R.sub.3 is lower alkyl (C.sub.2 -C.sub.3) or phenyl; or R.sub.2 and R.sub.3 together with the nitrogen atom form a morpholino ring, and pharmaceutically acceptable acid addition salts thereof, such as the hydrochloride.
While the above compounds evidence antiinflammatory properties, they also exhibit certain other properties which limit their utility as such drugs.
From the Canadian Journal of Chemistry (Vol. 47, pg. 2847, 1969) certain [2,1-b] thiazoles and thiazolo [3,2-a] pyrimidines are known as anthelmintics. 3-(Hydroxy- or methoxy)-phenyl-5,6-dihydroimidazo-[2,1-b] thiazoles are known from U.S. Pat. No. 2,969,369 to have a variety of pharmaceutical activities, including an antiinflammatory effect. Further, U.S. Pat. No. 3,860,718 describes the use of quaternary 7-substituted imidazo [2,1-b] thiazolium compounds as hypoglycemic agents (blood-sugar lowering agents), but no disclosure can be found therein which would indicate that such compounds have antiinflammatory properties.